Red List habitat classification > RL - Marine habitats > RLMED - Mediterranean > MEDA1.34 Communities of sheltered Mediterranean lower mediolittoral rock

Communities of sheltered Mediterranean lower mediolittoral rock

Quick facts

Red List habitat type code MEDA1.34
Threat status
Europe Data Deficient
EU Least Concern
Relation to
Source European Red List habitat factsheet
European Red List of habitats reports
European Red List of habitats (Excel table)

Summary

This habitat develops on the lower horizon of mediolittoral rock in areas sheltered from wave action and currents although some of the associated species may also thrive on moderately exposed shores. The rock surfaces are dominated by algae, the characteristic species depending on the local conditions. In areas of gently almost horizontal slopes, the red algae Ceramium ciliatum can form an almost continuous carpet. There may be distinctive crusts of the brown algae Nemoderma tingitatum on the smooth rocky shores where there is moderate to low wave action, and in nutrient enriched areas the green algae of the genus Ulva dominates and may exclude settlement of other species of algae.

Indicators of quality:
The only biotope which might be sensitive to pollution and man-induced impacts is that dominated by Nemoderma tingitanum. Reduction in the total percent cover of this species and overall species richness can indicate a decrease on ecological quality. Both the biotopes of Ceramium ciliatum and Ulva spp. show extraordinary resilience to environmental impacts and they appear even in degraded environments. A "Quality of Rocky Bottoms index" (CFR by its Spanish acronym) used in Spanish Atlantic waters for the assessment of macroalgae communities on rocky shores may have some potentially application in assessment of quality of this habitat.

Characteristic species
For full habitat description, please download the habitat factsheet.

Threat status

Synthesis of Red List assessment

This habitat has a wide geographical distribution but despite most of the Mediterranean coast being rocky, quantitative data on its extent is scarce. Given the past development of harbours, dikes and others coastal structures it is clear that the habitat has suffered a decline in extent. Expert opinion is that this has probably not exceeded 20% over the last 50 years and therefore the habitat is assessed as Least Concern for the EU 28 based on criteria A1 and B.
For EU28+, the habitat has a large EOO, and therefore it qualifies as Least Concern under Criterion B. However, the habitat is assessed as Data Deficient at EU 28+ level given the lack of information on its trends in quantity and quality and the fact that its overall distribution is unknown.
EU
Red List Category Red List Criteria
Least Concern -
Europe
Red List Category Red List Criteria
Data Deficient -

Confidence in the assessment

low
Red List of habitat categories and criteria descriptions

Pressures and threats

  • Urbanisation, residential and commercial development
    • Disposal of household / Recreational facility waste
    • Disposal of industrial waste
  • Pollution
    • Pollution to surface waters (limnic, terrestrial, marine & brackish)
    • Oil spills in the sea
  • Natural System modifications
    • Reclamation of land from sea, estuary or marsh
    • Infilling of ditches, dykes, ponds, pools, marshes or pits
  • Natural biotic and abiotic processes (without catastrophes)
    • Eutrophication (natural)

Habitat restoration potential

Unknown.

Trends in extent

Average current trend in quantity

Decreasing Decreasing
EU28 EU28+

Trends in quality

Average current trend in quality

Unknown Unknown
EU28 EU28+

Conservation and management needs

This habitat is widespread and common and therefore likely to be present within some protected areas although it may not be subject to specific conservation measures. Beneficial actions include those which improve water quality and the regulation of coastal development in order to avoid both direct and indirect damage. Further work is needed to identify management measures to support the conservation of this habitat including the establishment of reference sites to assist with monitoring trends.

List of conservation and management needs

  • Measures related to wetland, freshwater and coastal habitats
    • Restoring/Improving water quality
  • Measures related to spatial planning
    • Other marine-related measures
    • Establish protected areas/sites

Distribution

For each habitat a distribution map was produced from a wide variety of sources indicating known and potential occurrences of the habitat in 10x10 km grids within Europe. Occurrences in grid cells were given in two classes: actual distribution from relatively reliable sources (surveys, expert knowledge), and potential distribution based on models or less reliable indicators. Please download the fact sheet to see the map.

Geographic occurrence and trends

Seas Present or presence uncertain Current area of habitat (Km2) Recent trend in quantity (last 50 years) Recent trend in quality (last 50 years)
Adriatic Sea Present Unknown Unknown Decreasing
Aegian-Levantine Sea
Ionian Sea and the Central Mediterranean Sea
Western Mediterranean Sea

Extent of Occurrence, Area of Occupancy and habitat area

Extent of Occurrence (EOO) (Km2) Area of Occupancy (AOO) Current estimated Total Area Comment
EU28 2,000,004 359 Unknown EOO and AOO have been calculated on the available data. Although this data set is known to be incomplete the figures exceed the thresholds for threatened status.
EU28+ >359 Unknown EOO and AOO have been calculated on the available data. Although this data set is known to be incomplete the figures exceed the thresholds for threatened status.
AOO = the area occupied by a habitat measured in number of 10x10 km grid cells.
EOO = the area (km2) of the envelope around all occurrences of a habitat (calculated by a minimum convex polygon).

Characteristic species

The full list of characteristic species and genus are available above from the Summary. The species available in the EUNIS database are shown here.
Algae Callithamnion granulatum
Algae Ceramium ciliatum
Algae Chaetomorpha aerea
Algae Cladophora albida
Algae Cladophora laetevirens
Algae Cladophora sericea
Algae Cladophora vagabunda
Algae Corallina elongata
Algae Gastroclonium clavatum
Algae Hypnea musciformis
Algae Laurencia pyramidalis
Algae Nemoderma tingitanum
Algae Polysiphonia sertularioides
Algae Scytosiphon lomentaria
Algae Sphacelaria cirrosa
Algae Ulva fasciata
Invertebrates Chthamalus montagui
Invertebrates Ligia italica
Invertebrates Mytilus galloprovincialis
Invertebrates Pachygrapsus marmoratus
Invertebrates Patella caerulea
Invertebrates Patella ulyssiponensis
Invertebrates Stramonita haemastoma
Species scientific name English common name Species group
Callithamnion granulatum Algae
Ceramium ciliatum Algae
Chaetomorpha aerea Algae
Cladophora albida Algae
Cladophora laetevirens Algae
Cladophora sericea Algae
Cladophora vagabunda Algae
Corallina elongata Algae
Gastroclonium clavatum Algae
Hypnea musciformis Algae
Laurencia pyramidalis Algae
Nemoderma tingitanum Algae
Polysiphonia sertularioides Algae
Scytosiphon lomentaria Algae
Sphacelaria cirrosa Algae
Ulva fasciata Algae
Chthamalus montagui Invertebrates
Ligia italica Invertebrates
Mytilus galloprovincialis Invertebrates
Pachygrapsus marmoratus Invertebrates
Patella caerulea Invertebrates
Patella ulyssiponensis Invertebrates
Stramonita haemastoma Invertebrates

Vegetation types

Relation to vegetation types (syntaxa)

Not available

Other classifications

Not available
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